Mixmastermerrill Posted February 11, 2009 Report Posted February 11, 2009 I will be purchasing a 4mm crank kit with the cheetah jug and pistons. Just looking for some ideas. I have a coolhead with 22cc domes, boyson reeds, FMF gnarly pipes and an open aluminum air box with duel air filters. Different size domes? Different pipes? Should I go with a single carburetor kit? I was told that it Quote
rubberneck Posted February 11, 2009 Report Posted February 11, 2009 I am assuming you will be going with the 58x68mm cub which is 421 cc. It uses 68 mmblaster pistons and therefore you will need different domes for sure. Size of domes will be determined by what fuel you want to run. 20 cc domes gave me 190psi cranking compression which requires 110 octane. Before i get too carried away, what type of riding do you do? Cubs are top end motors. They are drag motors and make pretty killer hot duner motors. They suck on trails, so the cub may or may not be what you want anyway. You are definitely going to want different pipes. Most will recomend CPI or Shearers. You definitely do NOT want a single carb kit. A 421 cub is going to want 35 -39mm carbs. If you are concerned about ease of tuning, im not sure you are ready for a CUB. Not that it is any harder to tune, but you have to get it right or you will toast it. Keep in mind there are a lot of misc items you are going to need for a cub also. Pingle valve for sure, possibly an override/lockout, longer swingarm etc. What is your budget? Quote
vulvafan537240 Posted February 11, 2009 Report Posted February 11, 2009 rubberneck summed it up perdy well Quote
dajogejr Posted February 11, 2009 Report Posted February 11, 2009 IMO....and you can read a million topics on here about detuning a cub, if you plan on using your FMF pipes and an airbox with this particular cub setup, you're not ready. You're going to need at minimum a 6 over swingarm, stronger clutch...and I highly recommend a lockup and dunable override as well.... Quote
FireHead Posted February 11, 2009 Report Posted February 11, 2009 IMO....and you can read a million topics on here about detuning a cub, if you plan on using your FMF pipes and an airbox with this particular cub setup, you're not ready. You're going to need at minimum a 6 over swingarm, stronger clutch...and I highly recommend a lockup and dunable override as well.... I agree with most of that. You don't need a +6" swingarm with a cub. If you are an experienced rider, then a 4mil Cub can be run on a stock swingarm, assuming the bike has good a suspension setup. The only problem is that you have to be constantly aware of what the engine is doing. :geek: Quote
SonOfSand Posted February 11, 2009 Report Posted February 11, 2009 This is exactly the info i am looking for as well. I was planing on keeping my swing arm stock, I ride at 5000 feet, so if i did a 421 cub would the elevation take enough out of the engine to make it manageable with no extended swing arm? Do I have to run minimum 35 carbs to feed her, and how much dunning can i do on a tank of gas? I ride at St. Anthony, usually park at the egin lakes and ride down to choke cherry, will i make it back? My other option is a 4mm crank with stock jugs that are ported. Thanks for all your advice. Quote
Mixmastermerrill Posted February 11, 2009 Author Report Posted February 11, 2009 IMO....and you can read a million topics on here about detuning a cub, if you plan on using your FMF pipes and an airbox with this particular cub setup, you're not ready. You're going to need at minimum a 6 over swingarm, stronger clutch...and I highly recommend a lockup and dunable override as well.... I am aware that it will take some better parts to continue with this project and YES I am ready to build this bike! I Quote
2001Stroker Posted February 11, 2009 Report Posted February 11, 2009 You said in your first post, that you're building a Cheetah. Are you building a Cheetah Cub, or a Cheetah?. Just wondering, cause everyone's assuming that you're building a Cub. If you're building a Cheetah, that kinda puts a different twist on everything. Quote
dajogejr Posted February 11, 2009 Report Posted February 11, 2009 Putting a 4 mil cheetah or cub together with paddles and running a stock swingarm will be fun, make sure your life insurance is paid for....or get some afflack. I had a 4 mil cub on gas, and with a 6 over arm and 10 paddle haulers the front end came up, all the time...and I'm 250lbs. Sure...can you keep the front end down? yep.... Are you going to be able to use all the power that motor has even at 5000 feet. No way....sorry. Quote
00tbanshee Posted February 11, 2009 Report Posted February 11, 2009 i rode frans banshee out at glamis and it was a 421 cub with a stock swingarm.what a hand full and your sure can't get the full power out of it with the stock swingarm.imo i think it would be a waste of money to build a 421 cub and run a stock swingarm.like dave said get a good life insuriance plan for sure.keep in mind i have a 421 cub that i drag that has a +7 swinger with a bar so not saying i'm the best rider out there but sure no amateur with a cub. Quote
Mixmastermerrill Posted February 13, 2009 Author Report Posted February 13, 2009 You said in your first post, that you're building a Cheetah. Are you building a Cheetah Cub, or a Cheetah?. Just wondering, cause everyone's assuming that you're building a Cub. If you're building a Cheetah, that kinda puts a different twist on everything. Yes, it will be a Cheetah Cub. It will ONLY be raced a the drag strip. We have no sand in ALaska. Bummer! Snow, snow and mud. My buddy built his drag quad laast summer. He is one of those 4-stroke geeks. He built his own stretched frame. It looks damn good but he keeps popping chains. I so badly want to smoke his 4-stroke this summer. Quote
dajogejr Posted February 13, 2009 Report Posted February 13, 2009 I so badly want to smoke his 4-stroke this summer. That's easy....wait till he pops the chain...LOL Look into a lockup and override tranny. IF all you're gonna do is drag this bike, those two are an absolute must! Quote
rubberneck Posted February 13, 2009 Report Posted February 13, 2009 I agree with most of that. You don't need a +6" swingarm with a cub. If you are an experienced rider, then a 4mil Cub can be run on a stock swingarm, assuming the bike has good a suspension setup. The only problem is that you have to be constantly aware of what the engine is doing. :geek: I agree with firehead here. I only run a +2. Is it wheely happy. It can be, but not unrideable. All you guys make it sound like you need a 14 inch arm to ride one of these things. It just depends on what you are going to do with the bike. For a duner you dont need it. Can i do full throttle launch in 2nd and run with the drag guys no. But thats not what im doing with the bike. Tire selection has a huge part in this also. Try duning your long ass arms and let me know how that works out for you. Not arguing, im just saying. Now more back on track since we have determined that it will be a drag bike exclusively. You are silly not to do an override. You are going to want 35+ mm carbs, and drag pipes. why not go out of frames. I hear the new shearers are kicking ass. And for what you are doing, i think you will find you WILL need a lot longer swinger and or a wheely bar. For this listen to dajo, thats what he does. Quote
BellicoseBanshee Posted February 13, 2009 Report Posted February 13, 2009 Coming from 17 years of riding ATC250Rs, a 421 Cub on a stock swinger is not an out of control wheelie machine. As mentioned: if you dump it hard with a short swinger, you WILL be counting clouds. It depends on how the bike is being used, and what the bike is used for. I run the dunes all the time on an ATC-R (with haulers) without killing myself and riding out of control. Many would hop on my R and wheelie all the time and bitch that it won't turn. Doesn't make me an expert rider, because I am not, but it puts a little perspective on the subject. A 421 cub on a stock or +2 swinger used for hard duning and hillshooting is definitely manageable, but it is not going to be a monster off the line, period. With that being said, if you really want to launch it hard and use the cub's power as soon as the wheels start rolling, you had better plan on a longer swinger, for it is a given one cannot effectively "drag race" without it (lockout and override as well). How is that for riding the fence? :biggrin: Mixmastermerrill- if you are planning to drag race only, dajo is a wealth of information, and he knows what he is talking about- listen to him (If the this makes me a nut-swinger, I hope dajo is ok with the fact that I use jumper cable clips to attach myself to ones nuts :woot: )... Quote
dajogejr Posted February 13, 2009 Report Posted February 13, 2009 We're all pretty much saying the same thing... Is it rideable? Sure... Can you use some/most of the power effectively? Questionable. Can you flat out pin it and hope to not see your feet above your head? Doubt it....LOL. Quote
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